New Sanwa MT-44 4-channel 2.4GHz radio system
#272
Tech Rookie
What about steering wheel angle, is it possible to change?
#274
So, the 18650 battery is the way to go then? I have several of those and a slow charger. I can just solder the connector to them and still be able to drop a spare one into the charger and use the other one for a day at the races. If so, that's super cool!
#275
Tech Regular
iTrader: (4)
First set of batteries was bind and set up 5 cars with one day of racing 4-heats and 2-mains.
Second set was probably 6 practice sessions last week and one practice run on saturday
Third set radio shows 4.2 still and run time is 5:58.
It's better then my 11x but if I have to carry a pack AAA everywhere I guess I will
#277
Tech Addict
iTrader: (1)
I've used my new radio three days of practice/racing and I'm on my third set of batteries.
First set of batteries was bind and set up 5 cars with one day of racing 4-heats and 2-mains.
Second set was probably 6 practice sessions last week and one practice run on saturday
Third set radio shows 4.2 still and run time is 5:58.
It's better then my 11x but if I have to carry a pack AAA everywhere I guess I will
First set of batteries was bind and set up 5 cars with one day of racing 4-heats and 2-mains.
Second set was probably 6 practice sessions last week and one practice run on saturday
Third set radio shows 4.2 still and run time is 5:58.
It's better then my 11x but if I have to carry a pack AAA everywhere I guess I will
I'm using a 780mah 1S LiPo, not AAAs....
#278
The 18650 battery is still strong. It still sits at 4.0 after 6.5hrs of running, plus some idle setup time for my plane.
#279
Tech Initiate
Can anyone post a link for the MT44 manual English version. I can't find it anywhere on the internet. I ordered from Banzai Hobbies and mine is in Japanese.
#282
Not to start a war, but the MT-S seems like the best value. The speeds are identicle from the test I read on here.
Does anyone know the deal with Banzai? Every option with "Add to Cart" has a disclaimer that reads "backorder will be in stock within 1 week." Very discouraging.
Does anyone know the deal with Banzai? Every option with "Add to Cart" has a disclaimer that reads "backorder will be in stock within 1 week." Very discouraging.
#283
#284
The other thing I did as soon as I got my MT-44, was to compare response time to some other radios. I've been compiling a spreadsheet of this, along with some other information, and the results are enlightening to say the least!
In order to do the tests, I've been using a SkyRC ProgBox, which includes a PPM monitor feature. An understanding of how RC radios work is needed if you want to know what PPM is, so I'll cover that briefly first:
In order to do the tests, I've been using a SkyRC ProgBox, which includes a PPM monitor feature. An understanding of how RC radios work is needed if you want to know what PPM is, so I'll cover that briefly first:
The standard servo signal that's used by 90% of surface servos is based on an on-off pulse. The width of that pulse determines the position of the servo, with 1.5ms pulse width being the standard for centered position. The maximum and minimum pulse widths usually seen are 2.4ms and 0.6ms, but we usually use less than this range because we need less than 90 degrees of motion in either direction. This concept is called Pulse Position Modulation, or PPM.
In the days of analog servos, the rate at which these pulses were sent to a servo was at around 60 times per second. This rate limits the response of the servo, because there is a period of nearly 16.67ms between pulses (1/60 = 16.67ms), so the latency of the system could never be less than 16.67ms.
Digital signal processing used in digital servos allowed the pulse rate to be increased, reducing latency. It should be clear then, that the faster the rate the pulses are sent, the quicker the servo (or ESC) can react to a change. The fastest radio systems based on the 1.5ms neutral pulse width have a pulse frequency of around 384Hz, which means that pulses are being sent at 2.6ms. (1/384 = 2.6ms).
The limiting factor now becomes the 1.5ms neutral pulse width, because this standard allows the pulse to be up to 2.5ms wide, and if the pulse rate were to be faster than every 2.6ms, the width of the pulse could cause an overlap!
For this reason, a new 'Narrow Pulse' standard is available, where the pulse width is 0.3ms wide at neutral. If we assume a similar range as the 1.5ms pulse width, the largest pulse width for a narrow pulse system would be somewhere just under 0.5ms. Theoretically then, it should be possible to build a radio system with a less than 1ms response time. I've not seen that yet, but I have a big hole in my data because I've not yet measured the M12 and M12S... Hopefully tomorrow night I'll get a chance.
Before I get to my results, I should state that I'm measuring the lowest theoretical response time of the radio system. The actual radio transmission adds no measurable latency, but there could be some processing in the transmitter and receiver. I'm not able to measure that, and not making any claims about that either. I would think however, looking at the trends in the data, that at least of the Sanwa / Airtronics kit, the processing is what limits the PPM rate, so this is probably a very accurate way of measuring latency.
On to the results then:In the days of analog servos, the rate at which these pulses were sent to a servo was at around 60 times per second. This rate limits the response of the servo, because there is a period of nearly 16.67ms between pulses (1/60 = 16.67ms), so the latency of the system could never be less than 16.67ms.
Digital signal processing used in digital servos allowed the pulse rate to be increased, reducing latency. It should be clear then, that the faster the rate the pulses are sent, the quicker the servo (or ESC) can react to a change. The fastest radio systems based on the 1.5ms neutral pulse width have a pulse frequency of around 384Hz, which means that pulses are being sent at 2.6ms. (1/384 = 2.6ms).
The limiting factor now becomes the 1.5ms neutral pulse width, because this standard allows the pulse to be up to 2.5ms wide, and if the pulse rate were to be faster than every 2.6ms, the width of the pulse could cause an overlap!
For this reason, a new 'Narrow Pulse' standard is available, where the pulse width is 0.3ms wide at neutral. If we assume a similar range as the 1.5ms pulse width, the largest pulse width for a narrow pulse system would be somewhere just under 0.5ms. Theoretically then, it should be possible to build a radio system with a less than 1ms response time. I've not seen that yet, but I have a big hole in my data because I've not yet measured the M12 and M12S... Hopefully tomorrow night I'll get a chance.
Before I get to my results, I should state that I'm measuring the lowest theoretical response time of the radio system. The actual radio transmission adds no measurable latency, but there could be some processing in the transmitter and receiver. I'm not able to measure that, and not making any claims about that either. I would think however, looking at the trends in the data, that at least of the Sanwa / Airtronics kit, the processing is what limits the PPM rate, so this is probably a very accurate way of measuring latency.
- Sanwa MX-V: 63Hz / 15.9ms
- Sanwa MT-4 (Normal Mode): 90Hz / 11.1ms
- Sanwa MT-4 (SHR Mode): 192Hz / 5.2ms
- Sanwa MT-4 (SSR Mode - Narrow Pulse): 191Hz / 5.2ms
- Sanwa MT-4S (Normal Mode): 93Hz / 10.8ms
- Sanwa MT-4S (SHR Mode): 383Hz / 2.6ms
- Sanwa MT-S (FH4T Normal Mode): 95Hz / 10.5ms
- Sanwa MT-S (FH4T SHR Mode): 384Hz / 2.6ms
- Sanwa MT-S (FH4T SSR Mode - Narrow Pulse): 191Hz / 5.2ms
- Sanwa MT-S (FH3 Normal Mode): 83Hz / 12.0ms
- Sanwa MT-S (FH3 SHR Mode): 332Hz / 3.0ms
- Sanwa MT-44 (FH4T Normal Mode): 95Hz / 10.5ms
- Sanwa MT-44 (FH4T SHR Mode): 383Hz / 2.6ms
- Sanwa MT-44 (FH4T SSR Mode - Narrow Pulse): 383Hz / 2.6ms
- Sanwa MT-44 (FH3 Normal Mode): 83Hz / 12.0ms
- Sanwa MT-44 (FH3 SHR Mode): 332Hz / 3.0ms
#285
Tech Apprentice
iTrader: (2)
Keep in mind that I've owned both.
I'm not sure why they say that... It's happened every time I've placed an order, but they've shipped the next day. I wouldn't worry, but don't select shipping by sea; it takes forever!